Symptomatic lumbar mobile segment with spinal canal stenosis in a fused spine associated with diffused idiopathic skeletal hyperostosis

Background contextChronic, continuous stress at the junction of a stable/unstable site of the spine in diffuse idiopathic skeletal hyperostosis (DISH) has been reported to cause a nonunion. Back pain resulting from the nonunion has been rarely reported and few operative treatments have been suggested.PurposeTo report and discuss the pathogenesis, treatment, and surgical outcome of a rare cause of back pain.Study designCase report of back pain caused by a single lumbar segment is lacking bony union at the caudal end of a fused spine associated with diffuse idiopathic skeletal hyperostosis.MethodsBack pain in a 66-year-old man who had suffered for 10 years worsened. The back pain and thigh pain became intolerable, and the left buttock and thigh became numb. Radiographs and computed tomography images showed continuous hyperostosis in the anterior aspect of the vertebral bodies from C2 to L2. At the caudal adjacent level of these fused segments, L2/3 level was mobile and had canal stenosis. Decompression and posterior lumbar interbody fusion (PLIF) were performed.ResultsThe pain disappeared soon after the operation. The nonunited segment showed bony union at the 5-year follow-up.ConclusionsPLIF may be an option for surgically treating symptomatic nonunited lumbar segments at the caudal end of a fused spine with DISH in cases unresponsive to conservative treatment.